INS and obstructive sleep apnea syndrome: The eligible participants ranged from non-diabetic overweight/obese general individuals to patients with schizophrenia [31], obstructive sleep apnea [20], or polycystic ovary syndrome [25]; patients with type 1 diabetes mellitus (DM) [24, 28, 33]; various groups of type 2 DM patients, including drug-naïve patients [19, 41], those treated with insulin [18, 26, 40, 46], those with chronic kidney disease [22, 36], and those with cardiovascular disease [27, 30, 34].